Several years ago, the news broke that vitamin D may prevent colon cancer.

At the time, I realised that this type of news report would sow much confusion among the general public because the natural reaction of the man on the street would be to start taking vitamin D supplements in an attempt to prevent colon cancer.

The danger of excessive intakes of vitamin D also crossed my mind.

Since then, a variety of scientific articles have been published on the subject. These may shed some light on how much vitamin D the average South African requires and how this vitamin can be obtained.

Sources of vitamin D
The two main sources of vitamin D are oral ingestion of foods (particularly those that are fortified with vitamin D, such as most brands of margarine and some brands of packaged milk) or vitamin supplements, and exposure of the skin to sunlight, which causes the body to manufacture its own vitamin D.

Research has shown that western diets are often deficient in vitamin D, with elderly people ingesting considerably less vitamin D than required. However, the use of vitamin D supplements is associated with potential overdosing and interactions that can occur between vitamin D and other nutrients.

It is, however, relatively easy for most people in sunny South Africa to expose their skins to sunlight for short periods every day to make their own vitamin D.

It is estimated that an exposure lasting 20 minutes a day should be sufficient for most individuals to produce adequate vitamin D supplies in their bodies.

Slightly longer exposure times are required for people with black or brown skins because darker skins are not as efficient in producing vitamin D as white skins.

Persons with white skins should also not overdo sun exposure as this is linked to skin damage, eye damage, and the potentia ... Read more